Cluster box mail delivery unit



FIG. 1 is a perspective view of a cluster box mail delivery unit showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a top view thereof.

The rear and bottom views form no part of the claimed design.

The broken lines form no part of the claimed design. 

CLAIM The ornamental design for a cluster box mail delivery unit, as shown and described. 